1. Field of the Invention
The invention is related to digital integrated circuits and more particularly to synchronization circuits.
2. Description of the Related Art
In general, synchronization of digital signals transferred between asynchronous clock domains is performed using synchronizing devices (e.g., flip-flops) controlled by a destination clock signal. The asynchronous character of the interface can result in a data or control input changing at the instant of the destination clock signal transition. As a result, the synchronizing device becomes metastable, i.e., the output behaves unpredictably, taking many times longer than normal to settle to its correct state, or even oscillating several times before settling. In a typical computing system, metastability can cause data corruption and/or is fatal to program execution. Mean time between failures is a parameter that quantifies the capability of a destination device to resolve a metastable event. Mean time between failures is exponentially proportional to the destination clock period. Mean time between failures typically degrades with reduction of power supply voltage, which is the trend in digital integrated circuits.